Would it be pointless to pump CO2 into the intake of my Whisper 60? It
would be an easy modification and the impeller should do a fine job of
busting the CO2 bubbles up. This is a waterfall(?) type filter in that
it dumps the filtered water back on top of the water. Would the surface
agitation cause the CO2 to just dissolve back into the air?

I'm sure this is going to be hard to quantify but, how much water
surface agitation causes the CO2 to dissolve? I mean anything other
than stagnant water? Or does it have to be the white-water rapids?

TIA
my aquarium page, info and pics at:
www.geocities.com/spiral_72/Spirals_page.html